Putting effort into infant cognition.

Working memory allows for the manipulation of information in support of ongoing tasks, providing a workspace for cognitive processes such as learning, reasoning, and decision making. How well working memory depends, in part, on effort. Someone who pays attention at the right time and place will have better memory, and performance. In adult cognitive research studies, participants' devotion of maximal task-focused effort is often taken for granted, but in infant studies researchers cannot make that assumption. Here we showcase how pupillometry can provide an easy-to-obtain physiological measure of , allowing us to better understand infants' emerging abilities. In our work, we used pupillometry to measure trial-by-trial fluctuations of effort, establishing that, just as in adults, it influences how well infants could encode information in visual working memory. We hope that by using physiological measures such as pupil dilation, there will be a renewed effort to investigate the interaction between infants' attentive states and cognition.